Panametrics PanaFlow MV80, User Manual, Page: 179 / 184

PanaFlow™ MV80, MV82 & MV84 User’s Manual 167
Appendix D. Glossary
Reynolds Number
or Re



A dimensionless number equal to the density of a fluid times the velocity of the fluid times the diameter of the
fluid channel, divided by the fluid viscosity (i.e., Re = VD/

). The Reynolds number is an important number for
vortex flow meters because it is used to determine the minimum measurable flow rate. It is the ratio of the
inertial forces to the viscous forces in a flowing fluid.
RTD
Resistance temperature detector, a sensor whose resistance increases as the temperature
rises
scfm

Standard cubic feet per minute (flow rate converted to standard conditions,

as shipped 14.696 psia and 59° F). User definable.
Shedder Bar A non-streamlined body placed into a flow stream to create vortices. Also called a Bluff Body.
Strouhal Number
or St


A dimensionless number equal to the frequency of vortices created by a bluff body times the
width of the bluff body divided by the velocity of the flowing fluid (i.e., St = fd/V). This is an
important number for vortex flow meters because it relates the vortex frequency to the fluid
velocity.
Totalizer An electronic counter which records the total accumulated flow over a certain range of time
Traverse The act of moving a measuring point across the width of a flow channel
Uncertainty

The closeness of agreement between the result of a measurement and

the true value of the measurement
V Velocity or voltage
VAC Volts, alternating current
VDC Volts, direct current
VORTEX An eddy of fluid